North Jersey residents braced Saturday as Hurricane Irene began its dogged march up the coast.

More than a million people evacuated their homes in New Jersey. Public transportation shut down. Gas stations and grocery store shelves ran dry.

And then the region waited, wondering if the storm, which announced itself with a light rain throughout the day, would be remembered for an excruciating build-up or a devastating surge — or both.

“It’s been a long time since we’ve had a situation like this,” said North Jersey Weather Observers spokesman Bob Ziff.

In addition to the storm’s terrifying scope and force – tropical storm-force winds extended 290 miles from its center, and sustained winds were recorded in North Carolina at 85 mph – it threatened to spew as much as 10 inches of rain on an already waterlogged landscape, creating conditions for flooding along the Passaic, Ramapo and Saddle rivers into the week that could surpass some of the region’s most momentous storms.

“Before we got a drop of Irene moisture, this was the sixth-wettest August on record in New Jersey going back to 1895,” said David Robinson, the state climatologist. “The National Weather Service is already predicting ‘top 10’ flood events on all or portions of the Passaic River basin’s rivers.”

By Saturday night, the outer bands of the storm were already hitting New Jersey, with wind gusts as high as 55 mph in Atlantic City, State Climatologist David A. Robinson said. The worst of the storm was expected to arrive in Bergen County before dawn, with the highest winds and heavy rains pummeling the area until about midmorning and strong winds lingering until the afternoon, Robinson said.

By 8:30 p.m., the lower level of the George Washington Bridge was closed and the entire span will be shut if sustained winds reach 60 mph, the Port Authority said.

Governor Christie said the Oyster Creek nuclear power plant planned to power down to 30 percent capacity, a requirement when winds of more than 75 mph are expected.

But much of the early damage was expected to be caused by a storm surge of 4 to 8 feet above ground level, swamping low-lying areas from the Meadowlands to Battery Park in Manhattan with a wall of water and causing some rivers to swell to flood stage.

“We are going to have a lot of water coming into Newark Bay, the Hackensack River, the Passaic and New York Harbor,” said Alan F. Blumberg, director of the Center for Maritime Systems at Stevens Institute of Technology in Hoboken. “There’s a high probability that areas around the Meadowlands will be flooded. It makes no difference exactly where it makes landfall – we’re going to get a huge surge here.”

Blumberg added that the storm’s timing will be key.

He said high tide was expected at around 8 a.m. Sunday, and if the storm hits then, it could intensify flooding.

“If it arrives on either side of high tide, then look out,” he said.

Blumberg said the storm surge should start to recede about six hours after the storm hits.

Meteorologists also predict a backlash of winds from the counterclockwise rotation of the storm as it passes. And with many rivers not expected to peak until Tuesday, the full impact of Irene will not be clear for several days.

Shore is emptied

Such forecasts were dire enough to scatter residents from the region’s most flood-wary zones.

State police reported that more than a million people had evacuated from the Jersey Shore, and by 2 p.m. Sunday, 5,300 people were already in shelters across the state. Officials also ordered evacuations in parts of Hoboken and Jersey City.

Christie said Saturday that 1,500 National Guard soldiers and airmen had been deployed across 12 armories and at shelters to help evacuees.

The state was also ready to open the Izod Center, which can accommodate 1,700 people, and the Jersey City Armory, which can handle 750 more. Christie said flooding after the storm could also require evacuations, even away from the coast, as rivers rise.

“This is a storm of the century, and we really just want to be prepared,” said Dennis Robinson, president and CEO of the New Jersey Sports and Exposition Authority. “Should things turn for the worse, we’ll be available to pitch in.”

President Obama declared an emergency for New Jersey, which makes federal aid available to the state to supplement local response efforts because of the storm.

North Jersey evacuees included residents in Hillsdale, where firefighters spent Saturday morning knocking on doors to alert residents of a 4 p.m. mandatory evacuation in some areas. Lt. Tom Kelley said that about 90 percent of those he spoke with agreed to leave, compared to about 10 percent in a typical storm.

On Harding Avenue in Westwood, the air was filled with the sound of hammers hitting plywood as residents boarded up windows and doors. Others were busy putting sandbags in front of doors, basement windows and the like.

Pompton Lakes officials provided 250 tons of sand to residents, who prepared 6,000 sandbags to protect their homes from river flooding. Christie also ordered the gates of the Pompton Lake dam along the Ramapo River opened Friday afternoon, helping to lower the water level in Pompton Lake by 4 feet.

“A number of residents have evacuated already from seriously flood-prone areas, and our shelter is open to anyone who needs it at the Carnevale Center,” said Pompton Lakes Borough Administrator Vito Gadaleta.

“People should not take the lowering of the lake to indicate that there won’t be flooding,” Gadaleta said. “We’re asking everyone to take this storm seriously and for those in flood-prone areas to get out before the bulk of the storm hits.”

Several area medical facilities were also evacuated, and hospitals set up emergency command centers in advance of the storm.

Sunrise of Edgewater, an assisted-living facility, transferred about a dozen patients to Englewood Hospital on Saturday night, according to Michael Pietrowicz, a hospital vice president.

And Holy Name Medical Center transferred 12 patients from its residential hospice in Saddle River, the Villa Marie Claire, to the hospital in Teaneck.

In all, about 3,000 people at more than 20 health-care facilities were evacuated statewide, said Donna Leusner, a spokeswoman for the state Department of Health.

Shelters offered

The most vulnerable Passaic County residents were urged to make their way to the Red Cross Regional Center at Bergen County Community College in Paramus, which has a cot capacity of 450.

By 6 p.m., 27 adults and nine children had checked in -- some of them already reading and texting and lying back on their cots. About 500 more people were expected from Lodi, which had received evacuation orders earlier in the day.

“We’re going to be here how long?” asked Medjeene Lauture of Lodi, who was there with her 2-year-old child Makayla. Someone had rung her doorbell at 11 a.m., she said, telling her to evacuate.

“I just want to be here for my daughter,” she said. “I came because of her. If I didn’t have her, I would have stayed in the house. … I’m used to being on my own.”

People who did stay in their homes took extreme measures to prepare for the storm, with store owners reporting runs on emergency supplies, pumps running dry at gas stations and home- and business owners saying the forecasts drove them to take precautions they deemed unnecessary for previous storms.

“We’ve never had our windows boarded up before, but they’re doing it now,” said Sue Akin, a Pequannock resident and owner of Pompton Family Hair Center in Pompton Plains.

She also spent the day getting all the merchandise at least 18 inches off the ground, and with reason: Her flood-prone area got about 6 inches of water in March and 12 inches the spring before that. Those floods cost her business $10,000. “God knows they say this is going to be worse than we’ve seen in the last few years,” she said.

Two of the three gas stations at the corner of Closter Dock Road and Piermont Road in Closter had run dry by 1 p.m. Saturday, as people topped off their cars and filled gas cans for their backup generators.

“We’re completely out. We sold out of gas until there was nothing left in the ground,” said Brian Bourke of Closter Exxon.

Geno Paolucci, owner of Glen Rock Paint and Hardware, said he sold hundreds of flashlights and battery packs. Pumps, water vacuums, tarps, and tape were also flying off the shelves,

“At this point, people will take anything that will help,” said Eric Profe, manager of the Palmer Brothers Ace hardware store in River Edge. “The oil lamps are all gone. The lamp oil is gone. Even the wicks to use in the oil lamps are all gone.”

He also sold out of flashlights, extension cords, sump pumps, gas cans, generators and batteries. “I don’t think there is a D cell battery in New Jersey,” he said.

North Jersey residents braced Saturday as Hurricane Irene began its dogged march up the coast.

More than a million people evacuated their homes in New Jersey. Public transportation shut down. Gas stations and grocery store shelves ran dry.

And then the region waited, wondering if the storm, which announced itself with a light rain throughout the day, would be remembered for an excruciating build-up or a devastating surge — or both.

“It’s been a long time since we’ve had a situation like this,” said North Jersey Weather Observers spokesman Bob Ziff.

In addition to the storm’s terrifying scope and force – tropical storm-force winds extended 290 miles from its center, and sustained winds were recorded in North Carolina at 85 mph – it threatened to spew as much as 10 inches of rain on an already waterlogged landscape, creating conditions for flooding along the Passaic, Ramapo and Saddle rivers into the week that could surpass some of the region’s most momentous storms.

“Before we got a drop of Irene moisture, this was the sixth-wettest August on record in New Jersey going back to 1895,” said David Robinson, the state climatologist. “The National Weather Service is already predicting ‘top 10’ flood events on all or portions of the Passaic River basin’s rivers.”

By Saturday night, the outer bands of the storm were already hitting New Jersey, with wind gusts as high as 55 mph in Atlantic City, State Climatologist David A. Robinson said. The worst of the storm was expected to arrive in Bergen County before dawn, with the highest winds and heavy rains pummeling the area until about midmorning and strong winds lingering until the afternoon, Robinson said.

By 8:30 p.m., the lower level of the George Washington Bridge was closed and the entire span will be shut if sustained winds reach 60 mph, the Port Authority said.

Governor Christie said the Oyster Creek nuclear power plant planned to power down to 30 percent capacity, a requirement when winds of more than 75 mph are expected.

But much of the early damage was expected to be caused by a storm surge of 4 to 8 feet above ground level, swamping low-lying areas from the Meadowlands to Battery Park in Manhattan with a wall of water and causing some rivers to swell to flood stage.

“We are going to have a lot of water coming into Newark Bay, the Hackensack River, the Passaic and New York Harbor,” said Alan F. Blumberg, director of the Center for Maritime Systems at Stevens Institute of Technology in Hoboken. “There’s a high probability that areas around the Meadowlands will be flooded. It makes no difference exactly where it makes landfall – we’re going to get a huge surge here.”

Blumberg added that the storm’s timing will be key.

He said high tide was expected at around 8 a.m. Sunday, and if the storm hits then, it could intensify flooding.

“If it arrives on either side of high tide, then look out,” he said.

Blumberg said the storm surge should start to recede about six hours after the storm hits.

Meteorologists also predict a backlash of winds from the counterclockwise rotation of the storm as it passes. And with many rivers not expected to peak until Tuesday, the full impact of Irene will not be clear for several days.

Shore is emptied

Such forecasts were dire enough to scatter residents from the region’s most flood-wary zones.

State police reported that more than a million people had evacuated from the Jersey Shore, and by 2 p.m. Sunday, 5,300 people were already in shelters across the state. Officials also ordered evacuations in parts of Hoboken and Jersey City.

Christie said Saturday that 1,500 National Guard soldiers and airmen had been deployed across 12 armories and at shelters to help evacuees.

The state was also ready to open the Izod Center, which can accommodate 1,700 people, and the Jersey City Armory, which can handle 750 more. Christie said flooding after the storm could also require evacuations, even away from the coast, as rivers rise.

“This is a storm of the century, and we really just want to be prepared,” said Dennis Robinson, president and CEO of the New Jersey Sports and Exposition Authority. “Should things turn for the worse, we’ll be available to pitch in.”

President Obama declared an emergency for New Jersey, which makes federal aid available to the state to supplement local response efforts because of the storm.

North Jersey evacuees included residents in Hillsdale, where firefighters spent Saturday morning knocking on doors to alert residents of a 4 p.m. mandatory evacuation in some areas. Lt. Tom Kelley said that about 90 percent of those he spoke with agreed to leave, compared to about 10 percent in a typical storm.

On Harding Avenue in Westwood, the air was filled with the sound of hammers hitting plywood as residents boarded up windows and doors. Others were busy putting sandbags in front of doors, basement windows and the like.

Pompton Lakes officials provided 250 tons of sand to residents, who prepared 6,000 sandbags to protect their homes from river flooding. Christie also ordered the gates of the Pompton Lake dam along the Ramapo River opened Friday afternoon, helping to lower the water level in Pompton Lake by 4 feet.

“A number of residents have evacuated already from seriously flood-prone areas, and our shelter is open to anyone who needs it at the Carnevale Center,” said Pompton Lakes Borough Administrator Vito Gadaleta.

“People should not take the lowering of the lake to indicate that there won’t be flooding,” Gadaleta said. “We’re asking everyone to take this storm seriously and for those in flood-prone areas to get out before the bulk of the storm hits.”

Several area medical facilities were also evacuated, and hospitals set up emergency command centers in advance of the storm.

Sunrise of Edgewater, an assisted-living facility, transferred about a dozen patients to Englewood Hospital on Saturday night, according to Michael Pietrowicz, a hospital vice president.

And Holy Name Medical Center transferred 12 patients from its residential hospice in Saddle River, the Villa Marie Claire, to the hospital in Teaneck.

In all, about 3,000 people at more than 20 health-care facilities were evacuated statewide, said Donna Leusner, a spokeswoman for the state Department of Health.

Shelters offered

The most vulnerable Passaic County residents were urged to make their way to the Red Cross Regional Center at Bergen County Community College in Paramus, which has a cot capacity of 450.

By 6 p.m., 27 adults and nine children had checked in -- some of them already reading and texting and lying back on their cots. About 500 more people were expected from Lodi, which had received evacuation orders earlier in the day.

“We’re going to be here how long?” asked Medjeene Lauture of Lodi, who was there with her 2-year-old child Makayla. Someone had rung her doorbell at 11 a.m., she said, telling her to evacuate.

“I just want to be here for my daughter,” she said. “I came because of her. If I didn’t have her, I would have stayed in the house. … I’m used to being on my own.”

People who did stay in their homes took extreme measures to prepare for the storm, with store owners reporting runs on emergency supplies, pumps running dry at gas stations and home- and business owners saying the forecasts drove them to take precautions they deemed unnecessary for previous storms.

“We’ve never had our windows boarded up before, but they’re doing it now,” said Sue Akin, a Pequannock resident and owner of Pompton Family Hair Center in Pompton Plains.

She also spent the day getting all the merchandise at least 18 inches off the ground, and with reason: Her flood-prone area got about 6 inches of water in March and 12 inches the spring before that. Those floods cost her business $10,000. “God knows they say this is going to be worse than we’ve seen in the last few years,” she said.

Two of the three gas stations at the corner of Closter Dock Road and Piermont Road in Closter had run dry by 1 p.m. Saturday, as people topped off their cars and filled gas cans for their backup generators.

“We’re completely out. We sold out of gas until there was nothing left in the ground,” said Brian Bourke of Closter Exxon.

Geno Paolucci, owner of Glen Rock Paint and Hardware, said he sold hundreds of flashlights and battery packs. Pumps, water vacuums, tarps, and tape were also flying off the shelves,

“At this point, people will take anything that will help,” said Eric Profe, manager of the Palmer Brothers Ace hardware store in River Edge. “The oil lamps are all gone. The lamp oil is gone. Even the wicks to use in the oil lamps are all gone.”

He also sold out of flashlights, extension cords, sump pumps, gas cans, generators and batteries. “I don’t think there is a D cell battery in New Jersey,” he said.